This commit moves the TH structs and definitions to model. We don't want
oohelperd to depend on web_connectivity@v0.4.
Part of https://github.com/ooni/probe/issues/2240
A bunch of packages (including oohelperd) just need the ability to
use MaxMind-like databases. They don't need the additional functionality
implemented by the geolocate package. Such a package, in fact, is
mostly (if not only) needed by the engine package.
Therefore, move code to query MaxMind-like databases to a separate
package, and avoid depending on geolocate in all the packages for
which it's sufficient to use geoipx.
Part of https://github.com/ooni/probe/issues/2240
This diff introduces the following `oohelperd` enhancements:
1. measure both IP addresses resolved by the TH and IP addresses resolved by the probe;
2. when the URL scheme is http and there's no explicit port, measure both 80 and 443 (which will pay off big once we introduce support for optionally performing TLS handshakes);
3. include information about the probe and TH IP addresses into the results: who resolved each IP address, whether an address is a bogon, the ASN associated to an address.
This diff is part of https://github.com/ooni/probe/issues/2237
